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glibc  2.9
setuid.c
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00001 /* Copyright (C) 1998,2000,2003,2004,2006 Free Software Foundation, Inc.
00002    This file is part of the GNU C Library.
00003 
00004    The GNU C Library is free software; you can redistribute it and/or
00005    modify it under the terms of the GNU Lesser General Public
00006    License as published by the Free Software Foundation; either
00007    version 2.1 of the License, or (at your option) any later version.
00008 
00009    The GNU C Library is distributed in the hope that it will be useful,
00010    but WITHOUT ANY WARRANTY; without even the implied warranty of
00011    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
00012    Lesser General Public License for more details.
00013 
00014    You should have received a copy of the GNU Lesser General Public
00015    License along with the GNU C Library; if not, write to the Free
00016    Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
00017    02111-1307 USA.  */
00018 
00019 #include <errno.h>
00020 #include <unistd.h>
00021 #include <setxid.h>
00022 #include <linux/posix_types.h>
00023 #include <kernel-features.h>
00024 
00025 
00026 #ifdef __NR_setuid32
00027 # if __ASSUME_32BITUIDS == 0
00028 /* This variable is shared with all files that need to check for 32bit
00029    uids.  */
00030 extern int __libc_missing_32bit_uids;
00031 # endif
00032 #endif /* __NR_setuid32 */
00033 
00034 int
00035 __setuid (uid_t uid)
00036 {
00037   int result;
00038 
00039 #if __ASSUME_32BITUIDS > 0 && defined __NR_setuid32
00040   result = INLINE_SETXID_SYSCALL (setuid32, 1, uid);
00041 #else
00042 # ifdef __NR_setuid32
00043   if (__libc_missing_32bit_uids <= 0)
00044     {
00045       int saved_errno = errno;
00046 
00047       result = INLINE_SETXID_SYSCALL (setuid32, 1, uid);
00048       if (result == 0)
00049        goto out;
00050       if (errno != ENOSYS)
00051        return result;
00052 
00053       __set_errno (saved_errno);
00054       __libc_missing_32bit_uids = 1;
00055     }
00056 # endif /* __NR_setuid32 */
00057 
00058   if (uid == (uid_t) ~0
00059       || uid != (uid_t) ((__kernel_uid_t) uid))
00060     {
00061       __set_errno (EINVAL);
00062       return -1;
00063     }
00064 
00065   result = INLINE_SETXID_SYSCALL (setuid, 1, uid);
00066 # ifdef __NR_setuid32
00067  out:
00068 # endif
00069 #endif
00070 
00071   return result;
00072 }
00073 #ifndef __setuid
00074 weak_alias (__setuid, setuid)
00075 #endif